1. Field of Invention
This invention relates to spanner wrenches. More particularly, this invention relates to spanner wrenches for use in the construction industry for tightening or loosening pipe coupling assemblies.
2. Description of Prior Art
Spanner wrenches are utilized for applying torque to pipe coupling assemblies to effect a secure, leak-proof joint. The spanner wrench is applied to raised lugs which are circumferentially spaced about the assembly for engagement by the similarly spaced tooth-shaped members of the spanner wrench. Representative spanner wrenches are depicted in U.S. Pat. No. 1,882,462, Weber, and in U.S. Pat. No. 2,830,480, Brame.
The repeated application of spanner wrenches on the raised, radially projecting lugs of pipe coupling assemblies has caused problems in the past for the wrenches have slipped and damaged the raised lugs and/or have stripped the threads within the assembly. Furthermore, when working in tight quarters, such as occur when electrical lines are run through pipes that are positioned adjacent to walls, or ceilings, or within shallow raceways, the clearance needed to effectively apply torque to the pipe coupling assemblies has been lacking and the assemblies have not been made up properly.
Since spanner wrenches have proven ineffective in tight places, chain wrenches have been tried in lieu thereof. The chain wrenches, however, are cumbersome, for the free end of the chain must be passed radially about the lugs on the assembly and must then be pulled tightly about the pipe assembly joint to take up the slack in the chain. The stiffness of the chain makes secure engagement difficult to achieve. Thus, when one applies a torquing action to the pipe wrench, the wrench may slip, damage the lugs, and lead to an imperfect joint.